Study of Light Emitting Diode (LED) And High-Pressure Sodium Vapour (HPSV) Lamp Based on Photometric Method for Road Lighting in Malaysia

Road lighting plays an important role for assisting traffic safety and ease of passage for road users. It also contributes to reducing crime and contributes to commercial and social use for towns at night. For motorists, road lighting ensures sufficient information is received in the field of vison. High Pressure Sodium Vapour (HPSV) lamps are currently the common type of road lighting, but the current trend is shifting to Light Emitting Diodes (LED). One of the main objectives of shifting from HPSV lighting systems to LED lighting systems is to reduce energy while maintaining sufficient brightness. Replacement of a complete luminaire as the current practice is expensive and requires a large capital cost. This study analyses measurements of light intensity distribution profiles to evaluate the implications of transforming an existing HPSV luminaire to an LED luminaire using an LED lamp. In this work, goniophotometric measurement results are used to compare and analyze photometric characteristics which are total luminous flux, Backlight-Uplight-Glare (BUG) rating and the Light Intensity Distribution (LID) Curve. The results showed that HPSV fitting with LED lamp gave similar LID pattern but with a reduced luminance value outperformed retrofit LED luminaires with a light output ratio (LOR) about 50% lower. This large decline seems to be due to the LED lamp structure, which takes up a major area inside the HPSV luminaire housing. In the future, studies utilizing different types of LED lamp structure and light fittings may have different results. Investigation of the different lamp substitutions ought to be performed to avoid decreasing the required light output and affecting the safety of road users. Therefore, after such a light source replacement is carried out, photometric dispersion should be evaluated.